Cognitive function
The cognitive function of the subjects in this study was measured
using Korean versions of the MoCA (MoCA-K) and
MMSE (MMSE-K). The MoCA was developed as a quick
screening instrument for mild cognitive dysfunction, a cut ofscore 26 out of 30 being normal (Nasreddin et al., 2005).
MoCA-K is a Korean version of the MoCA designed by
Nasreddine et al. (2005). Lee et al. (2008) modified and then
translated it into Korean and assessed its validity. Based on 30-point scale, the difference in cognitive ability depending
on education is adjusted by adding 1 point for those with less
than 6 years of education. This tool classifies those scoring
< 23 points as having cognitive dysfunction (Lee et al., 2008).
The Korean version of MMSE is a standard tool published
by Psychological Assessment Resources, and based on an original conceptualization by Folstein et al. (1975). It consists
of 30 questions on temporal orientation, spatial orientation,
memory registration, attention and calculation, recall, language
skills, and visuospatial construction ability. Based on a
30-point scale, 1 or 0 point is given for each activity, depending
on its fulfillment. This study distinguishes dementia by
using the age-education controlled cutoff score for dementia
established by the Ministry of Health & Welfare, Korea
(2010).
In this study, the criteria for MCI were that cognitive function
had declined (MoCA-K < 23), but not low enough to be
classified as dementia (MMSE age-education controlled
cutoff score).